Create karaoke beatmap encoder/decoder for testing purpose

[andy840119]

Not really sure will Json become default osu beatmap, might be yes 🤔 . If that so, can create something like KaraokeJsonBeatmapDecoder or KaraokeAlphaBeatmapDecoder. And the final goal is remove KaraokeLegacyBeatmapDecoder because it sucks.

What's the step :

• Create KaraokeJsonBeatmapEncoder and KaraokeJsonBeatmapDecoder
• Register some convertor in IO/Serialization/Converters
• Add button to import/export json beatmap (think about extension name.)
• Replace and modify default config setting(CreateGlobalSettings in JsonSerializableExtensions).
• Test it and check is there any serializer need to be added(e.g. ColorSerizlider).

Step about remove KaraokeLegacyBeatmapDecoder

• Check where user this class
• Replace some testing beatmap into json format if needed.
• [Notice] Should change testing beatmap into json format.
• Remove old code.

[andy840119]

Got the answer is yes to might can make this first.

[andy840119]

Also need to search is there any way to convert reference object into json string.

[andy840119]

Json encoder/decoder already implemented. Also, already made the debug beatmap manager for able to export/override the json beatmap.